1. Field of the Invention
The present invention relates to a method for neutralizing and decontaminating solid residue adhered onto munition bodies of abandoned chemical weapons.
2. Description of the Related Art
Chemical weapons or chemical munitions using highly toxic chemical agents such as mustard and lewisite have been known for some time. A recent discovery has revealed that substantial amounts of unprocessed chemical weapons are still left buried underground or dumped in lakes or sea in certain regions. This fact poses a serious threat to human lives and has become a major social concern. The decontamination of these chemical weapons is thus an urgent task.
Chemical munitions have generally been processed according to the following steps:    (1) fixing a chemical munition recovered from underground or the like, boring the munition bodies using a disassembling machine or the like, inserting a nozzle into the bore, and feeding an alkaline solution, e.g., a NaOH solution, at normal temperature from the nozzle so that the alkaline solution can circulate therein to wash away and hydrolyze liquid chemical agents;    (2) mechanically separating a burster from the munition shell by cutting, and destroying the burster by a separate explosive destruction process;    (3) fixing the munition shell to the disassembling machine for the second time, allowing an alkaline solution, e.g., a NaOH solution, at a high temperature to circulate to dissolve the solid residue (hereinafter also referred to as “heel”) remaining in the munition shell until chemical agents are eliminated, and hydrolyzing the solid residue; and    (4) discharging the circulated solution into a reaction vessel, allowing the circulated solution to react with an oxidant at a high temperature, so as to oxidize the intermediate products resulting from decomposition of the chemical agents into stable salts.
However, the surface of the heel remaining in the munition shell has an insoluble coat resulting from high-polymeric modification of chemical agents due to long-term abandonment. Thus, the heel cannot be sufficiently dissolved even with a strong alkaline solution at a high temperature, thereby inhibiting hydrolysis. One possible solution is to cut the insoluble coat of the heel or the heel itself into minute pieces in advance; however, such cutting requires high precision and complicated steps, resulting in a longer processing time and inefficiency, which is a problem.